To improve combustion of the mixture introduced into a combustion chamber of an internal combustion engine, numerous devices and methods have been proposed in recent years, permitting a more environmentally compatible combustion of the mixture, it being known for the pressure in one or more of the combustion chambers to be measured. The advantage of measuring the pressure in a combustion chamber here is that the heat released during a combustion process in the combustion chamber can be calculated, in order to improve subsequent combustion processes by altering injection parameters.
Since the injection conditions, for example the geometry of the injection nozzles, can change over the service life of the internal combustion engine, it is advantageous if the variation over time of the pressure in this combustion chamber is known for each of the combustion chambers, in order to optimize the combustion process individually. However, measuring the pressure in each of the combustion chambers, for example using a pressure sensor built in to the spark plug, has the disadvantage that it is cost-intensive, since a pressure sensor must be provided for each of the combustion chambers. A further disadvantage is that each of these pressure sensors must be connected to the engine control evaluating the pressure signals.